New async notification API. Removed obsolete surround. Cleaning

src/async.c

@@ -0,0 +1,114 @@
+/*
+ *  Async notification helpers
+ *  Copyright (c) 2001 by Abramo Bagnara <abramo@alsa-project.org>
+ *
+ *   This library is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU Library General Public License as
+ *   published by the Free Software Foundation; either version 2 of
+ *   the License, or (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU Library General Public License for more details.
+ *
+ *   You should have received a copy of the GNU Library General Public
+ *   License along with this library; if not, write to the Free Software
+ *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+#include "pcm/pcm_local.h"
+#include "control/control_local.h"
+#include <signal.h>
+
+static struct list_head snd_async_handlers;
+
+static void snd_async_handler(int signo ATTRIBUTE_UNUSED, siginfo_t *siginfo, void *context ATTRIBUTE_UNUSED)
+{
+	int fd;
+	struct list_head *i;
+	assert(siginfo->si_code = SI_SIGIO);
+	fd = siginfo->si_fd;
+	list_for_each(i, &snd_async_handlers) {
+		snd_async_handler_t *h = list_entry(i, snd_async_handler_t, glist);
+		if (h->fd == fd) {
+			h->callback(h);
+			// break;
+		}
+	}
+}
+
+int snd_async_add_handler(snd_async_handler_t **handler, int fd, 
+			  snd_async_callback_t callback, void *private_data)
+{
+	snd_async_handler_t *h;
+	int was_empty;
+	h = malloc(sizeof(*h));
+	if (!h)
+		return -ENOMEM;
+	h->fd = fd;
+	h->callback = callback;
+	h->private_data = private_data;
+	was_empty = list_empty(&snd_async_handlers);
+	list_add_tail(&h->glist, &snd_async_handlers);
+	*handler = h;
+	if (was_empty) {
+		int err;
+		struct sigaction act;
+		act.sa_flags = SA_RESTART | SA_SIGINFO;
+		act.sa_sigaction = snd_async_handler;
+		sigemptyset(&act.sa_mask);
+		err = sigaction(SIGIO, &act, NULL);
+		if (err < 0) {
+			SYSERR("sigaction");
+			return -errno;
+		}
+	}
+	return 0;
+}
+
+int snd_async_del_handler(snd_async_handler_t *handler)
+{
+	int err = 0;
+	list_del(&handler->glist);
+	if (list_empty(&snd_async_handlers)) {
+		struct sigaction act;
+		act.sa_flags = 0;
+		act.sa_handler = SIG_DFL;
+		err = sigaction(SIGIO, &act, NULL);
+		if (err < 0) {
+			SYSERR("sigaction");
+			return -errno;
+		}
+	}
+	if (handler->type == SND_ASYNC_HANDLER_GENERIC)
+		goto _end;
+	list_del(&handler->hlist);
+	if (!list_empty(&handler->hlist))
+		goto _end;
+	switch (handler->type) {
+	case SND_ASYNC_HANDLER_PCM:
+		err = snd_pcm_async(handler->u.pcm, -1, 1);
+		break;
+	case SND_ASYNC_HANDLER_CTL:
+		err = snd_ctl_async(handler->u.ctl, -1, 1);
+		break;
+	default:
+		assert(0);
+	}
+ _end:
+	free(handler);
+	return err;
+}
+
+int snd_async_handler_get_fd(snd_async_handler_t *handler)
+{
+	return handler->fd;
+}
+
+void *snd_async_handler_get_callback_private(snd_async_handler_t *handler)
+{
+	return handler->private_data;
+}
+